S&CO INC BRK/B — D BERKSHIRE HATHAWAY INC DEL CL B

Ownership history in S&CO INC  ·  96 quarters on record

AI Ownership Summary

S&CO INC reported D BERKSHIRE HATHAWAY INC DEL CL B (BRK/B) in 96 quarterly 13F filings from 2023 Q4 through 2026 Q1. Peak portfolio weight reached 5.92% in 2025 Q1. The latest visible filing shows BRK/B at 4.88% of the fund.

This page tracks quarterly shares, estimated market value, portfolio weight, filing dates, and disclosure-aligned stock prices directly from SEC EDGAR 13F filings. Older history is available after unlock; the visible window still shows the most recent pattern.

What this BRK/B ownership page tells you

This page is designed to answer the real investor question behind a 13F filing: how meaningful was S&CO INC's position in D BERKSHIRE HATHAWAY INC DEL CL B, and how did that conviction change over time? You can read the holding window, peak weight, latest reported size, disclosure timing, and quarter-by-quarter changes without piecing the story together from raw SEC rows.

Freshest filing
Latest Reported Filing
2026 Q1

BRK/B was reported at 4.88% of portfolio in the most recent visible filing.

High-water mark
Peak Conviction
5.92% in 2025 Q1

Peak weight helps separate a token disclosure from a real conviction holding the fund genuinely cared about.

Time in book
Holding Window
2023 Q4 to 2026 Q1

Longer holding windows often tell a very different story from short-lived tactical trades or one-quarter experiments.

Decision context
Why It Matters
Position size beats headlines

Knowing that a fund owned a stock is useful. Knowing whether it was a 0.20% placeholder or a true high-conviction position is where the signal actually starts.

BRK/B stock page S&CO INC fund profile S&CO INC full holdings
How S&CO INC held BRK/B — position size vs. price
% of Fund (quarterly)
📋 Quarterly Holdings History 10 quarters  ▾
Quarter Action Sold % After 3M Timing Shares Change Chg % % of Fund Mkt Value Filed Price (Filed)
2026 Q1 REDUCED — — — 164,075 -155 -0.1% 4.88% $79K 2026-05-07 $469.32
2025 Q4 REDUCED — — — 164,230 -734 -0.4% 5.13% $82.5M 2026-02-05 $503.89
2025 Q3 REDUCED — — — 164,964 -1,030 -0.6% 5.08% $82.9M 2025-11-06 $493.15
2025 Q2 ADDED — — — 165,994 +373 +0.2% 5.17% $80.6M 2025-08-07 $461.47
2025 Q1 REDUCED — — — 165,621 -64 -0.0% 5.92% $88.2M 2025-05-08 $513.25
2024 Q4 UNCHANGED — — — 165,685 — 0% 5.10% $75.1M 2025-02-07 $472.74
2024 Q3 ADDED — — — 165,685 +1,830 +1.1% 4.98% $76.3M 2024-11-07 $460.13
2024 Q2 REDUCED — — — 163,855 -900 -0.5% 4.65% $66.7M 2024-08-08 $431.54
2024 Q1 REDUCED — — — 164,755 -1,395 -0.8% 4.88% $69.3M 2024-05-09 $408.82
2023 Q4 REDUCED — — — 166,150 -542 -0.3% 4.54% $59.3M 2024-02-12 $397.71
86 older quarters hidden  —  Sign in free or upgrade to Premium to see full history

🏢 Other funds also holding BRK/B

As of 2026 Q1 — sorted by position size

TETRAD CORP 92.15% 1922 Investment Co LLC 3Y 7Y 84.86% CHECK CAPITAL MANAGEMENT INC/CA 3Y 7Y 52.8% Cook & Bynum Capital Management, LLC 3Y 7Y 42.7% Templeton & Phillips Capital Management, LLC 3Y 36.02% Aquamarine Zurich AG 3Y 34.57% Ardent Capital Management, Inc. 3Y 32.73% Asset Management Advisors, LLC 3Y 7Y 32.43% United American Securities Inc. (d/b/a UAS Asset Management) 3Y 7Y 31.97% Pacifica Capital Investments, LLC 3Y 7Y 30.79%

FAQ About S&CO INC and BRK/B

These are the practical questions this page is built to answer before you even open the full history table.

How long has S&CO INC reported owning BRK/B?

S&CO INC reported BRK/B across 10 quarterly 13F filings, from 2023 Q4 through 2026 Q1.

What was the largest reported BRK/B position in S&CO INC's portfolio?

The largest reported portfolio weight for BRK/B was 5.92% in 2025 Q1.

What is the latest reported BRK/B position on this page?

The most recent filing on this page is 2026 Q1, when S&CO INC reported 164,075 shares, equal to 4.88% of portfolio, with an estimated market value of $79K.

What does the chart on this BRK/B ownership page compare?

The chart compares S&CO INC's quarterly BRK/B portfolio weight with the stock's indexed share price, so you can see whether the fund was building, trimming, or holding the position as price moved.

How well did S&CO INC time their BRK/B position?

Based on 13F filing dates vs. subsequent BRK/B price moves, S&CO INC correctly timed 32 out of 86 reported position changes (37%). The annualised alpha on BRK/B relative to SPY over the holding period was +1.5%.

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